1. Field of the Invention
This invention relates to a chemical conversion device that comprises an outside chamber that contains at least one internal heat transfer module. The module comprises a preferably pressure-resistant metal jacket. This chamber generally comprises several modules that are connected to one another by flexible connecting means. All of these modules, through which at least one most often gaseous reagent is circulated, form a reactor. The invention was carried out in particular within the scope of the implementation of reactions that require at start-up either an input of calories or an input of kilogram calories. The applications of the reaction chamber of the invention for carrying out reactions are, for example, reactions of steam-cracking, pyrolysis, catalytic dehydrogenation, vaporeforming or water-vapor reforming, or thermal cracking, for example of hydrogen sulfide (H2S). More particularly, the application of the invention is in carrying out endothermic reactions in which the reaction temperature is usually greater than about 250° C., often greater than about 350° C., and most often greater than about 500° C., and where one of the problems to be solved is to limit the secondary reactions that lead to the formation of tar and/or coke.
2. Description of the Prior Art
Many documents describe reactors that make it possible to work at high temperature, in general greater than about 350° C., and in a potentially coking environment where the catalytic effects of the metal walls should be avoided.
The reactor that was described in U.S. Pat. No. 5,554,347 comprises several rows of heating means and/or heat extraction means. This document describes: a reactor that comprises heating means that are fed by a mixture of combustible gas and oxygen carrier that make it possible to generate the power that is necessary for the reaction, and walls of a particular shape that make possible both an increase of the heat transfers because of between-wall radiative exchanges and a monitoring of the dwell time of gases in the reactor.
U.S. Pat. No. 5,321,191 that describes a reactor that is used for implementing a process for thermal pyrolysis of hydrocarbons comprising several rows of electric heating means encased by sheaths arranged in layers that are approximately parallel to one another and perpendicular to the axis of the reactor so as to define passages for the circulation of gas mixtures and/or effluents between the sheaths and/or between the sheaths and walls that separate two layers of parallel sheaths is also known.
The implementation of these technologies offers many advantages relative to previously developed ceramic technologies, for example the one that is described in U.S. Pat. No. 4,780,196 that relates to the steam-cracking of hydrocarbons in order to produce essentially light olefins, for example ethylene and/or propylene, as well as the one that is described in U.S. Pat. No. 4,973,777 that relates to the thermal conversion of methane into hydrocarbons of higher molecular weight.
According to the teaching of French Patent No. 2 802 119, a significant improvement that relates to the connecting means between the jacket of the reactor and the walls that are located on both sides of a heating pipe is also known. The improvement consists in the cooperation of a bellows, a packing box and a flange attached to the jacket of the reactor so as to ensure a relatively flexible connection between this jacket and a pipe that constitutes a heat exchange means. Such a connecting device is described as making it possible to limit the risks of the pipe rupturing in the cases where the latter becomes offset. Thus, a better sealing is ensured, which is reflected by a limitation of the loss of a portion of the reagents used in the reactor.
Relative to these teachings of the prior art, significant improvements can also be provided.